But the pagan Celts also believed it was a time when the walls between our world and the next became thin and porous, allowing spirits to pass through.

The practice of donning a scary costume may have stemmed from this belief, and the idea that dressing up as a ghost may have scared away other ghosts.

The classic Hallowe’en jack-o’-lantern, a carved grinning pumpkin, seems to have come from an old Irish legend of a man called Stingy Jack, a miserly farmer who played a trick on the devil and as punishment was cursed to wander the earth, lighting his way with a candle inside a hollowed-out turnip.

When the tradition moved to America pumpkins were used instead of turnips, as they were both more available and easier to carve.